Coil-winding machine



COIL-WINDING MACHINE 8 Sheets-Sheet 1 Filed Feb. 14, 1955 Nov. 10, 1959 .1.A. oRAM Erm.

COIL-WINDING MACHINE 8 Sheets-Sheet 2 Filed Feb.l 14, 1955 .Il ill N\\ 1 u QQ mm 0 M. T uw m JL E mw WS NS %N\ QS .QS

Nov. 10, 1959 J, A. oRAM ETAL coIL-wmnmc; MACHINE Filed Feb. 14,V 1955 8 Sheets-Sheet 3 n 1| NN O NQ NS Nov. 10, 1959 J. A. oRAM ErAL coIL-w1NDING MACHINE 8 Sheets-Sheet 4 Filed Feb. 14, 1955 v mi Nov. l0, 1959 J. A. oRAM ETAL 2,912,177

coIL-wINnING MACHINE:

Filed Feb. 14, 1955 8 sheets-sheet 5 Nov. 10, 1959 J. A. CRAM ETAL 2,912,177

COIL-WINDING MACHINE I Filed Feb. 14, 1955 8 Sheets-Sheet 6 Nov. 1o, 1959 J. A. @RAM m1 2,912,177

COIL-WINDING MACHINE Filed Feb. 14, 1955 8 Sheets-Sheet 'Z Nov. 10, 1959 J. A. ORAM ETAL COIL-WINDING MACHINE Filed Feb. 14, 1955 8 Sheets-Sheet 8 Unite rates Patent his coIL-wlNniNG MACHINE Application February I14, y1955, serial No. 487,846

Claims priority, application Great Britain February 16, 1954 '5 Claims. (Cl. 242-9) This invention relates to coil-winding machines and is particularly applicable to the manufacture of potentiometer cards for use in analogue computers and similar apparatus.

Such potentiometer cards generally comprise a carrier in the form of a rigid thin strip of either uniform or varying width on which is Wound a line wire having, for example, a diameter of 0.0020 inch. The wire must be laid on the carrier with a high degree of accuracy and there must be no possibility of displacement of the turns of wire once they have been laid.

An important object of the invention is, therefore, to provide a machine which ensures the desired degree of accuracy of laying and immobility of the coils when laid and which is nevertheless simple in construction and operation.

Another object of the invention is to provide means for ensuring that each turn of wire is laid in a corresponding notch cut by the machine in an edge of the card.

A further object of the invention is to provide a coil- Winding machine having a notching tool for cutting Wirereceiving notches in an edge of the card, the notching tool being adjustable to cater for different wire diameters and different coil pitches.

A further object of the invention is to provide a machine having means for guiding the wire right onto the card.

A still further object of the invention is to provide a machine wherein the card is correctly and accurately positioned so that the wire is wound evenly round the card and the depth of the notches remains constant.

The machine in accordance with the invention comprises an annular head mounted for rotation round the card and means for effecting relative movement between the head and the card along the length of the card, in which the head carries a notching tool for cutting notches in an edge of the card and a supply of wire which, as the head rotates, is paid out over a guide so disposed on the annular head relatively to the notching tool that the wire is received by a notch almost immediately after the notch is formed.

Preferably, the notching tool and the wire guide are so arranged relatively to one another that the Wire is received in the notch before the head has rotated through more than about after the notch has been cut. Thus, if the card is being wound with, for example, 50 turns to the inch (a relatively coarse pitch) the notch will have moved less than 0.001 inch and there can be no possibility of the wire being inaccurately laid.

vIn the best form of the machine, the annular head rotates about a spring-loaded clamp which yieldingly grips the card as it passes through the head and which is provided with a surface projecting from the face of the head which serves to guide the wire into the notches. This clamp also has anV aligning surface against which an edge of the card is made to bear so that the depth of the notches does not vary as the card is moved through the head.

The notching tool preferably cuts V-shaped notches which allows the Wire to centre itself in them v automatically.

In order that the invention may be thoroughly understood a coil-winding machine in accordance with it will now be described with reference to the accompanying drawings, in which:

Figure l is a plan view of the machine;

Figure 2 is a side elevation of the machine with parts shown in section;

Figure 3 is pant of the plan view shown in Fig. l drawn to an enlarged scale;

Figure 4 is part of the side drawn to an enlarged scale;

Figure 5 is an enlarged section taken on the line V-V in Fig. 3;

Figure 6 is an enlarged section taken on the line VI-VI in Fig. 3;

Figure 7 is a perspective View of part of the machine;

Figure 8 is an enlarged vertical section through the annular head; and

Figures 9-11 are detailed views of the notching tool, Fig. ll being a section taken on the line `Xl*-XI in Fig. 10.

The machine resembles a lathe and comprises a base '10 on which is mounted an electric motor 12. `The motor 12 serves to drive a pair of shafts 14 and 16 extending the length of the machine through gearing 18, .19 and 20 and belt-drives 22 and 24. The gear and belt drive ratios may be varied to vary the speeds of rotation of the shafts 14 and 16.

vThe shaft 14 is journalled at its end remote from the motor in a rigid support 26 which carries an annular wire- Winding head 28. The annular head 28 is mounted for rotation on the support by means of ball-bearings 30 (see Fig. 8) and is provided with a toothed ring 32 which engages with a gear-wheel 34 on the shaft `14 so that the head can be driven by the motor I1.2.

The other shaft 16 is screw-threaded along almost its entire length and passes through a screw-threaded hole 35 in a card-support 36 which is mounted for sliding movement along the bed 38 of the machine. The support 36 is similar to the tool post of a latheand has a pairv of auxiliary slides 40 and `42. The function of the support 36 is to move the potentiometer card shown at 44 through the annular wire-Winding head 28' while the latter is being rotated around the card.

The annular wire-winding head 28 is provided on its elevation shown in Fig. 2

face 46 with a radially-arranged notching blade 48, the

adapted to cut notches at regular intervals along the edge l Si) of the card as a the card while the the head.

The blade `48 and the manner in which it is mounted on the head is shown in greater detail in Figs. 9-11. The blade 48 is sharpened so as to cut V-shaped notches and is held in a slot 52 cut in a support 54 fixed to the head by screws 56. The blade is so mounted that it can be adjusted both towards and away from the face 46 of the head and towards and away from the card for the purpose of varying the depth of the notches cut in the edge result of the rotation of the head round latter is being moved axially through of the card. The adjustment towards and away from the l. face 46 is effected by rotation of a timely-threaded screw from the card is eifected by rotation of the key 60 which comprises two cylindrical portions 60a and 60h joined by an eccentric portion 60C. The eccentric portion 60e is made to lie in a transverse slot 62 in the blade so,`r`

that rotation of the key causes the blade 48 to be moved along the slot 52. A small stop 64 prevents the blade from slipping out of the slot. Y

Also mounted on the face 46 of the annular head is a bobbin of wire 66 which is payed out as the head rotates aboutthe card and laid in the notches as they are formed in the edge 50 of the card. After being unwound from off the bobbin, the wire passes over a roller 68 carried on the end of a tension arm 70 which is pivotally mounted at 80 on a brake arm 71 which is pivotally mounted on the head at 82 and is provided with a brake-pad 84 which bears on the rim of the bobbin. The arm '70 is cut away at 72 to clear the pivotal mounting 82, and the lower end of the tension arm 70 is connected to a fixed projection 74 on the head by means of a tension spring 76.

The arm 70 is further provided with an extension 78 carrying a stop screw 79. The tension arm 7d serves to maintain the payed out wire under tension irrespective of the quantity of wire on the bobbin, even under conditions where, owing to the off center position of a narrow card, some wire has to be taken back` during a portion of the winding cycle. When the arm 70 reaches the limit of its travel towards the center of the head, the stop screw 79abuts against the brake arm 71. Any further demand for wire causes the arm 70 and the brake arm 71 to swing as one unit about the pivot 82, thus lifting the brake-pad and permitting wire to be payed out.

After having passed over the roller 68 on the tension arm 70, the wire passes over a pulley 86 mounted close to the notching blade 48. The relative disposition of this pulley and the notching blade is important and is such that the wire is received by each notch almost immedi# ately after the notch is cut. In the specific machine being considered, the relative disposition is such that the wire is received in each notch before the head has rotated more than about 10 after the notch has been cut.

The provision of the notches along one edge of the card ensures that there is no possibility of displacement of the turns of wire once they have been laid, and the fact that the wire is laid in each notch so soon after the notch has been cut leads to a high Ydegree ofv accuracy in the spacing of the individual turns of wire. A further advantage of the machine is the manner in which the notching blade may be adjustedrboth radially and axially on the head.

It is, of course, necessary to feed the card through the annular head very carefully so that the spacing between individual turns of wire does not vary and so that the depth of the notches cut does not vary along the card. Accordingly, a clamp 88 is arranged within the cylindricalspace in the annular head, the clamp serving to grip the card lightly and'maintain it in a horizontal plane. The construction of the clamp is shown clearly in Figs. 5, 6 and 8. It comprises a pair of jaws 90 and 92 having opposed clamping surfaces of Z-outline as shown in Figs. and 6, the upper jaw 90 being mounted for limited swinging movement about the horizontal pivots 94 towhich it is joined by a U-shaped lever 96. A compression spring 98 urges the upper jaw 90 downwards towards the lower jaw 92. The extent to which the jaw 90 can swing about the pivots 94 is very small indeed as the variation in card thicknesses does not demand that the jaw 90 should move away from the lower jaw 92 more than a small fraction of'an inch.

The card -is gripped between the horizontal portions ofthe opposed clamping surfaces of the jaws and this ensures immobility of the card vertically. it is, however, essential that the edge 50 of the card be maintained in such a position that the depth of the notches cut in that edge remains the same along the card. The edge 50 is therefore made to bear against the vertical portion 198 of the clamping surface of the lower jaw 92 (see Fig. 6). The edge-of the card is held against this aligning surface 198 by means of a special linkage which will now be described.

The card is gripped at each of its ends by two simple clamps and 102 which form part of a partiallycompleted frame 104, and A107. The card and the frame 104, 105 and 107 together form a complete rigid rectangular frame which is pivotally connected at one end to a supporting part 106 on the auxiliary slide 42 of the sliding support 36, and at the other end to a weight 108 by means of a cable 110 passing over a pulley 112 on the` end of the machine. The connection between the side 105 of the frame and the part 106 on the slide 4Z is provided by Vtwo 1iinks 114 and 116 of equal length pivotally attached to the side 10S at 118 and 120 and pivotally attached at their other ends to a cross-bar 122 rigidly connected to the supporting part 106. The side 105, the links 114 and 116, and the cross-bar 122 thereby form a parallelogram linkage.

It will be seen from Fig. 3 that the links 114 and' 116 are out-of-line with the axis of the potentiometer card. The weight 108 pulling on the far end of the card therefore tends to align the links and the card with each other, and in so doing causes the edge 50 of the card to be pressed against the vertical aligning surface 198.

The reason why the jaws 9) and 92 of the card clamps S8 have Z-shaped opposed clamping surfaces is to prevent the wire being wound on the card from slipping into the gap between the jaws. It is also to be noted that the front parts of the jaws project from the face 46 of the head. These parts of the jaws are shaped to provide a guide surface 124 over which the wire slides before it enters each notch. The wire is thereby guided right onto the card and this ensures accurate laying of each turn of wire in the appropriate notch.

A revolution counter 126 is provided for counting the revolutions of the annular head 28. The drive for the counter is taken olf the shaft 14 by means of a spindle 128.

In order that the rotation of the head and the movement of the card may be stopped once the card has been wound with the required number of turns of wire, a limit switch 130 is provided on the head which is actuated by a projection 132 adjustably mounted on the frame side 104.

We claim:

1. A machine for winding a coil of wire on a card, comprising a base-portion, driving means mounted on said base-portion, an annular head mounted for rotation on said base portion and drivingly-connected to said driving means, means for holding said card in a plane such that said annular head rotates round said card, means on said head adapted to carry a supply of wire, said means for holding said card having a bearing surface, means comprising a linkage pivotally attached to one end of said card, said linkage being pivotally attached at a different part thereof to a member out-of-line with the axis of said head, tensioning means for placing said card and said linkage in tension whereby said linkage and said card tend to align themselves with each other and said edge of the card is thereby pressed against said bearing surface.

2. A coil-winding machine as claimed in claim 1, wherein said tensioning means comprise a weight attached to the end of said card remote from said linkage.

3. A coil-winding machine as claimed in claim l, including a partially-completed frame to which said card is xedly attached, said card and said partially-completed frame together forming a rigid rectangular frame structure.

4. A coil-winding machine as claimed in claim l, wherein said head surrounds a card clamp, said clamp having two jaws and said bearing surface being formed on one of said jaws.

5. A machine for winding a coil of wire on a card, comprising a base-portion, driving means mounted on said base-portion, an annular head mounted for rotation on said base-portion and drivingly-conuected tosaid driving means, means for holding said card in a plane such that said annular head rotates round said card, means driven by said driving means for eiiecting relative movement between said head andsaid card along the length of said card, a notchlng tool carried by said head for cutting notches in an edge of said card, a supply of wire carried by said head, guide means on said head for guiding said wire as said Wire is payed out, said wire-guide means being disposed on said head relatively to said notching tool whereby said payed-out wire is received by a notch in said edge of the card almost immediately after said notch is formed, said means for holding said card including a card clamp suiTounded by said head, a card-aligning surface on said clamp, means for making the edge of said card bear against said aligning surface, said means comprising a partially-completed frame, said means for holding said card including xing means on said frame whereby said card may be attached thereto to form a side of said frame, a pair of links of equal length pivotally connected to one end of said frame, a bar member pivotally connected to said links whereby said end of said frame, said links and said bar member form a parallelogram linkage, said bar member being drivingly connected to said driving means.

References Cited in the le of this patent UNITED STATES PATENTS 1,887,808 Havlish Nov. 15, 1932 2,360,960 Martindell Oct. 24, 1944 2,393,548 McCoy Jan. 22, 1946 2,406,846 Muller Sept. 3, 1946 2,569,292 Dehmel Sept. 25, 1951 

